This invention provides for an improved press machine, and particularly for a stroke controllable press machine which is suitable for processing workpiece with a variety of specifications, particularly for working used hardware.
The press machine is vital machine in modern manufacturing, and it has the advantages of punching, shearing, shaping, bending and compressing functions. However, a press machine with only a treadle drive system or a hydraulic system cannot be completely controlled when punching and is not suitable to punch differently shaped workpiece.
FIG. 1 is a front view of a prior press machine which comprises a press bed 1 which has two spaced apart upright supporting arms 11, 12; each supporting arm 11, 12 has a slide groove 13 on it, a transmitting shaft 14 mounted horizontally on the upper portion of the supporting arm 11, 12 and a flywheel 141 connected to one end of the shaft 14. The flywheel 141 can be actuated by motor 16; a crank means 142 is connected to the shaft 14 and also to a slide body 17 which can be slid up and down on the groove 13 of the supporting arm 11, 12. There is a clutch device 141a between the flywheel 141 and transmitting shaft 14. The clutch device 141a is disengaged while in a normal state and controlled by a treadle 15 so that the flywheel 141 cannot engage the shaft 14 for rotating until the treadle is pressed down. When the motor 16 is switched on, it actuates the flywheel 141 by a belt 16a for syncronous rotation. When an operator wishes to press a workpiece placed on the bed 1, he presses on the treadle 15 and engages the clutch 141a between the flywheel 141 and the shaft 14 by the clutch rod 151 to start the syncronous rotation. By means of the crank 142, the slide body 17 can be slid up and down along the slide groove 13 to perform the punching and pressing function. Because the above-described prior press machine has a punching stroke which cannot be adjusted, it is very limited in the types and sizes of workpieces that it can press, and specifications cannot be varied. For special processing of workpieces of various specifications and shapes, the prior press machine is not convenient or suitable, because it is difficult to locate a differently shaped workpieces at proper position with respect to the punch.